Patterned magnetic media via thermally induced phase transition

ABSTRACT

High areal storage density, patterned magnetic media comprising a patterned plurality of at least partially crystalline, ferromagnetic particles or grains are provided by means of a simple, economical process wherein a non-magnetic substrate is provided with a layer of an amorphous, paramagnetic or anti-paramagnetic material comprising at least one component, e.g., a metal element, which is ferromagnetic when in at least partially crystalline form, and at least partially crystallizing the at least one component at selected areas of the amorphous layer to form a spaced-apart pattern of at least partially crystallized, ferromagnetic particles or grains of the at least one component, the particles or grains being spaced apart and surrounded by a matrix of the amorphous material. Embodiments include utilizing a focussed or scanned laser source and an amorphous Ni—P layer for forming ferromagnetic Ni particles or grains.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.09/593,243, filed Jun. 14, 2000, now U.S. Pat. No. 6,387,530, whichclaims priority from provisional application No. 60/151,029, filed Aug.27, 1999.

CROSS-REFERENCE TO PROVISIONAL APPLICATION

This application claims priority from U.S. provisional patentapplication Serial No. 60/151,029 filed Aug. 27, 1999, the entiredisclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to improved magnetic data/informationrecording, storage and retrieval media and to a method for manufacturingsame. More specifically, the present invention relates to improved, highareal recording and storage density, patterned magnetic media and to amethod for manufacturing same which can be readily practiced at a lowcost comparable to that of conventional multi-grain magnetic media.

BACKGROUND OF THE INVENTION

Magnetic media are widely utilized in various applications, particularlyin the computer industry, and efforts are continually made with the aimor increasing the areal recording density, i.e., the bit density, orbits/unit area, of the magnetic media. Conventional magnetic thin-filmmedia, wherein a fine-grained polycrystalline magnetic alloy layerserves as the active recording medium layer, are typically formed as“perpendicular” or “longitudinal” media, depending upon the direction ofmagnetization of the grains. In this regard, the “perpendicular”recording media have been found superior to the more common“longitudinal” media in achieving very high bit densities. However, asgrain sizes decrease in order to achieve increased recording bitdensities, e.g., to somewhere around 20 Gb/in², effects ansing fromthermal instability, such as “super-paramagnetism” are encountered. Oneproposed solution to the problem of thermal instability with ultra-highrecording density magnetic recording media is to increase thecrystalline anisotropy, and thus the squareness of the bits, in order tocompensate for the smaller grain sizes.

An alternative approach, however, to the formation of very high bitdensity magnetic recording media, is one which delays the onset ofthermal instability problems by storing the data/information in isolatedmagnetic particles. In contrast with conventional polycrystalline-basedmagnetic media where thousands of very small-sized grains are requiredfor storing a single data bit, so-called “patterned” magnetic mediautilize only a single, relatively large-sized particle for storage of asingle data bit. For example, in “patterned” media, the single particles(i.e., the basic storage unit) are more than about ten times larger thanthe thermally unstable grains of conventional very high recordingdensity magnetic media, in principle permitting storage densities ofabout 100 Gb/in² and above.

Analogous to the situation with conventional polycrystalline thin filmmagnetic media, both “longitudinal” and “perpendicular” types ofpatterned magnetic media have been developed, depending upon whether themagnetization direction of the particles is parallel or perpendicular tothe media surface. When fabricated in disk form, such “patterned” mediaare readily adapted for use in conventional hard drives, with most ofthe drive design features remaining the same. Thus, hard-drive based“patterned” media technology would comprise a spinning disk with aslider head flying above it in closely-spaced relation thereto, withread sensors or a read/write head that magnetizes and/or detects themagnetic fields emanating from the magnetic particles.

To date, several approaches have been utilized for the formation of“patterned” magnetic media, which approaches can be classified into twomajor categories, i.e., (1) mechanical or mechanical replication; and(2) lithographic patterning.

According to the first approach, as exemplified by the Atomic ForceMicroscopy (“AFM”) approach of IBM (B. Terris et al., Data Storage,August 1998, pp. 21-26), a sharp tip is utilized for scanning extremelyclose to the surface of a storage medium. The tip is located at the endof a flexible cantilever, which deflects in response to changes in theforce imposed on the tip during scanning. The force may arise from avariety of effects, including, inter alia, magnetic force. To date, twotypes of AFM drives have been demonstrated, i.e., write-once/read-onlyand read-only. The former type of AFM drive, which provideswrite-once/read-only capability, utilizes a heated AFM tip for writingonce by forming small indentations or pits in the surface of asubstrate. e.g., of polycarbonate. Data is read by using the AFM tip toscan the thus-indented surface and sensing the changes in the forceimposed on the AFM tip due to the presence of the indentations.

The latter type of AFM drive functions in a read-only mode, and data isinitially written in the form of indentations (pits) which are createdin the surface of a SiO₂ master by means of an electron beam. The data,in the form of the indentations, is then transferred, by replication, toa photopolymer-coated glass substrate, which photopolymer is cured byexposure to ultra-violet (UV) radiation to thereby form a surfacetopography representing the data. The data is then read from the curedphotopolymer surface by scanning with the AFM tip to sense the changesin force thereat due to the indentations.

According to the second, lithographic approach, thin film processes suchas are utilized in the fabrication of semiconductor integrated circuitsincluding micro-sized features are adapted for making high aspect ratio,single column/bit, perpendicularly patterned media. According to oneparticular approach (M. Todorovic et al., Data Storage, May 1999, pp.17-20), designed to increase coercivity, hence stability, of theindividual magnetic columns, electroplated nickel (Ni) is utilized forforming the columns, and gallium arsenide (GaAs) and alumina (Al₂O₃) areemployed as embedding media for the columns. The fabrication processstarts with an electrically conductive GaAs substrate, on which thinlayers of aluminum arsenide (AlAs) and GaAs are successively deposited.Scanning electron-beam lithography is then utilized to define the magnetpatterns on a resin-coated sample. The patterns in the e-beam exposedresin are developed utilizing an appropriate solvent system and thentransferred, as by chemically-assisted ion beam etching (“CAIBE”), intothe AlAs/GaAs layers. After pattern definition, the AlAs layer isconverted into Al₂O₃ by wet thermal oxidation. The thus-producedpatterned layer acts as a mask for additional etching for extending thepattern of depressions perpendicularly into the GaAs substrate. Theetched depressions in the Al₂O₃ substrate are then filled withelectroplated Ni. Overplated Ni “mushrooms” are then removed, as bypolishing, to create a smooth surface for accommodating slider contacttherewith.

Thus, the overall process sequence for forming such media requiressuccessive, diverse technology steps for (1) MBE growth and maskdeposition; (2) electron beam lithography; (3) chemically assisted ionbeam etching; (4) wet thermal oxidation; (5) chemically assisted ionbeam etching; and (6) electroplating and polishing. The result is acomplex and time-consuming fabrication process. Moreover, each of theabove-described approaches for patterned media manufacture typicallyinvolves substantial capital investment for the process equipment, whichtogether with the inherent process complexity, render them too costlyfor use in high product throughput, magnetic disk media manufacture.

Accordingly, there exists a need for improved, high bit density,patterned magnetic data/information recording, storage, and retrievalmedia, e.g., in hard disk form, and a method for manufacturing same,which can be implemented at a cost compatible with that of conventional,multi-grain disk media by primarily utilizing current mediamanufacturing methodologies, technologies, and instrumentalities.

The present invention, therefore, addresses and solves problemsattendant upon patterned magnetic media manufacture, and affords rapid,cost-effective fabrication of high bit density, patterned magneticmedia, e.g., in the form of hard disks, while providing substantiallyfull compatibility with all mechanical and electrical aspects ofconventional hard disk technology. Moreover, the patterned magneticmedia of the present invention can be simply and reliably manufacturedlargely by means of conventional manufacturing techniques.

DISCLOSURE OF THE INVENTION

An advantage of the present invention is an improved method ofmanufacturing a high areal storage density, patterned magneticdata/information recording, storage and retrieval medium.

Another advantage of the present invention is an improved, high arealstorage density, patterned magnetic data/information recording, storageand retrieval medium.

Additional advantages, aspects, and other features of the presentinvention will be set forth in the description which follows and in pantwill become apparent to those having ordinary skill in the art uponexamination of the following or may be learned from the practice of thepresent invention. The advantages of the present invention may berealized and obtained as particularly pointed out in the appendedclaims.

According to an aspect of the present invention, the foregoing and otheradvantages are obtained in pant by a method of manufacturing a highareal storage density, patterned magnetic recording, storage andretrieval medium, which method comprises the sequential steps of:

(a) providing a non-magnetic substrate having a surface for layerformation thereon;

(b) forming a layer of an amorphous, paramagnetic or anti-paramagneticmaterial on the substrate surface, the layer of amorphous, paramagneticor anti-paramagnetic material comprising at least one component which isferromagnetic when in at least partially crystalline form; and

(c) at least partially crystallizing the at least one component of thelayer of amorphous, paramagnetic or anti-paramagnetic material atselected locations thereof to thereby form a pattern of at leastpartially crystalline, ferromagnetic particles or grains of the at leastone component of the layer, the ferromagnetic grains being spaced apartand surrounded by a matrix of the amorphous, paramagnetic oranti-paramagnetic material.

According to embodiments of the present invention, step (b) comprisesforming as the amorphous, paramagnetic or anti-paramagnetic layer ametal glass layer including at least one metal element which isferromagnetic when in at least partially crystallized form, e.g., themetal glass layer comprises at least one of iron (Fe), nickel (Ni), andcobalt (Co); and step (c) comprises at least partially crystallizing theat least one component of the amorphous, paramagnetic oranti-paramagnetic layer by increasing the temperature thereof at theselected locations, e.g., increasing the temperature at the selectedlocations up to at least a phase transition temperature of the at leastone component.

According to further embodiments of the present invention, step (c)comprises increasing the temperature of the amorphous, paramagnetic oranti-paramagnetic layer to up to the melting point of the at least onecomponent thereof, e.g., by irradiating the layer with photons orenergetic particles at the selected locations, such as by photonirradiation utilizing a focussed laser or a focussed, high-intensitylamp as a photon source, or by utilizing an electron beam source as asource of energetic particles.

According to still further embodiments of the present invention, step(c) comprises scanning the photons or energetic particles across thesurface of tile amorphous, paramagnetic or anti-paramagnetic layer toimpinge at the selected locations thereof, or irradiating the photons orenergetic particles through an aperture-patterned mask having aplurality of openings therethrough with predetermined dimensionscorresponding to a preselected size of the at least partiallycrystalline, ferromagnetic particles or grains; the pattern beingtwo-dimensional and defining a checkerboard or other shape pattern ofthe at least partially crystallized, ferromagnetic particles or grainssurrounded by the amorphous, paramagnetic or anti-paramagnetic layer.

According to further exemplary embodiments of the present invention:

step (a) comprises providing a non-magnetic, disk-shaped substratecomprising a material selected from the group consisting of metals,metal alloys, aluminum (Al), Al-based alloys, ceramics, glasses,polymers, and composites thereof;

step (b) comprises forming a layer of amorphous nickel-phosphorus (Ni—P)as the amorphous, paramagnetic or anti-paramagnetic material; and

step (c) comprises increasing the temperature of the amorphous Ni—Player at the selected locations to a temperature, e.g., up to about 350°C., for an interval sufficient to form and at least partiallycrystallize ferromagnetic Ni particles or grains thereat.

According to another aspect of the present invention, a high arealstorage density, patterned magnetic data/information recording, storageand retrieval medium comprises:

a non-magnetic substrate having a surface: and

a patterned magnetic layer on the substrate surface, the patternedmagnetic layer comprising a plurality of spaced-apart, at leastpartially crystalline, ferromagnetic particles or grains surrounded by amatrix of an amorphous, paramagnetic or anti-paramagnetic material.

According to embodiments of the present invention, the non-magneticsubstrate comprises a material selected from the group consisting ofmetals, metal alloys, aluminum (Al), Al-based alloys, ceramics, glasses,polymers, and composites thereof; and the patterned magnetic layercomprises a plurality of spaced-apart, at least partially crystalline,ferromagnetic particles or grains comprising at least one metal elementwhich is ferromagnetic when in at least partially crystalline form,selected from the group of metal elements consisting of iron (Fe),nickel (Ni), and cobalt (Co), the particles or grains being surroundedby a matrix comprised of a metal glass paramagnetic or anti-paramagneticlayer including at least one of the aforementioned metal elements.

According to further embodiments of the present invention, thenon-magnetic substrate is disk-shaped; and the patterned magnetic layercomprises a plurality of spaced-apart, at least partially crystalline,ferromagnetic Ni particles or grains surrounded by a matrix of amorphousNi—P.

According to still further embodiments of the present invention, thepatterned magnetic layer comprises a two-dimensional, checkerboardpattern of at least partially crystalline, ferromagnetic particles orgrains and a surrounding matrix of amorphous, paramagnetic oranti-paramagnetic material; and the magnetic medium further comprises aprotective overcoat layer over the patterned magnetic layer and alubricant topcoat layer over the protective overcoat layer.

According to yet another aspect of the present invention, a magneticmedium comprises:

a non-magnetic substrate including a surface; and

patterned magnetic means formed within a layer of amorphous material onthe substrate surface.

According to an embodiment of the present invention, the patternedmagnetic layer means comprises a plurality of spaced-apart, at leastpartially crystalline, ferromagnetic particles or grains surrounded by amatrix of amorphous, paramagnetic or anti-paramagnetic materialcomprising at least one component which is ferromagnetic when in atleast partially crystalline form.

Additional advantages and aspects of the present invention will becomereadily apparent to those skilled in the art from the following detaileddescription, wherein embodiments of the present invention are shown anddescribed, simply by way of illustration of the best mode contemplatedfor practicing the present invention. As will be described, the presentinvention is capable of other and different embodiments, and its severaldetails are susceptible of modification in various obvious respects, allwithout departing from the spirit of the present invention. Accordingly,the drawing and description are to be regarded as illustrative innature, and not limitative.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of an embodiment of the invention canbest be understood when read in conjunction with the following drawings,wherein:

FIGS. 1(A) and 1(B), respectively, show cross-sectional and plan viewsof a Ni—P plated, Al-based substrate prior to patterned Nicrystallization processing;

FIGS. 2(A) and 2(B), respectively, show cross-sectional and plan viewsof the Ni—P plated, Al-based substrate subsequent to irradiation with afocussed heat source for inducing patterned Ni crystallization;

FIGS. 3(A) and 3(B) are drawings of image patterns of Ni—P plated,Al-based substrates after high power laser irradiation to temperaturesclose to the Ni—P melting point, obtained via Atomic Force Microscope(AFM) and Magnetic Force Microscopy (MFM), respectively; and

FIGS. 4(A) and 4(B) are drawings of image patterns of Ni—P plated,Al-bascd substrates after low power laser irradiation to temperaturesbelow the Ni—P melting point, obtained via AFM and MFM, respectively.

DESCRIPTION OF THE INVENTION

The present invention has, as a principal aim, provision of a simple,convenient, and reliable method of forming magnetic patterns on orwithin substrate surfaces, for use in manufacturing high areal densitydata/information recording, storage and retrieval media suitable foroperation with conventional disk drive technology, which method relieslargely upon techniques, methodologies, and instrumentalities currentlyutilized in the manufacture of magnetic media. The present inventionalso has, as a principal aim, provision of high areal density, patternedmagnetic data/information recording, storage and retrieval media, e.g.,hard disks, which can be manufactured at a cost compatible with that ofconventional, multi-grain magnetic media.

An essential feature of the patterned magnetic media of the presentinvention, and manufacturing method therefor, is the formation on asurface of a suitable substrate, such as a non-magnetic disk, of apattern of spaced-apart, individual ferromagnetic particles or grainssurrounded by a matrix comprised of an amorphous, paramagnetic oranti-paramagnetic material, whereby minimal magnetic coupling occursbetween closely-spaced, e.g., adjacent, particles or grains. Theferromagnetic particles or grains are arranged in a regular, i.e.,orderly, pattern for facilitating data recording, storage, andretrieval. As indicated supra, patterned magnetic media of the typecontemplated herein, when fabricated to include appropriatelydimensioned magnetic particles or grains with no, or very littleinter-grain coupling, can exhibit very high areal recording densities,e.g., on the order of about 100 Gb/in² and greater.

The present invention also avoids the drawbacks and disadvantages ofearlier patterned magnetic recording media resulting from the use oftechnologically diverse, complicated, and capital-intensivemanufacturing procedures, equipment, and methodology. In contrast withsuch prior fabrication methodologies, the present invention can bepracticed by utilizing materials, techniques, and methodologies commonlyand currently employed in the manufacture of conventional multi-grainmagnetic recording media.

According to a first step of the present invention, as shown in FIGS.1(A) and 1(B) in cross-sectional and plan view, respectively, aconventionally utilized substrate 1, e.g., a disk-shaped substratecomprised of a non-magnetic material selected from among metals, metalalloys, aluminum (Al), Al-based alloys, glasses, ceramics, polymers, andall manner of composites thereof, is initially provided, and anappropriate thickness film or layer 2 of an amorphous, paramagnetic oranti-paramagnetic material is formed on a major surface 1M thereof, asby a suitable amorphous thin film deposition technique (e.g., chemicalvapor deposition (CVD); plasma enhanced CVD (PECVD); physical vapordeposition (PVD), including sputtering, vacuum evaporation, ion plating,etc.; electroless plating; and electroplating). An essential feature ofthe present invention is that the amorphous, paramagnetic oranti-paramagnetic material be comprised of at least one component, whichwhen present in at least partially crystallized form, exhibitsferromagnetism. Suitable materials for such amorphous, paramagnetic oranti-paramagnetic layer include, inter alia, metallic glasses comprisedof one or more metallic elements which exhibit ferromagnetism when in atleast partially crystallized form, notably iron (Fe), nickel (Ni), andcobalt (Co).

Referring now to FIGS. 2(A) and 2(B), which respectively showcross-sectional and plan views, according to a second step of thepresent invention, a plurality of areas arranged in a preselectedpattern on the surface of the layer or film 2 of amorphous, paramagneticor anti-paramagnetic material are selectively converted into individualferromagnetic particles or grains 3, as for example, by a phasetransition involving local melting and subsequent crystallization. Suchphase transition by melting/crystallization can be readily achievedselectively and locally by means of a variety of processes and sources 4for locally applying thermal energy beams 5 to the upper surface 2U oflayer 2, such as, for example, by laser heating, high-intensity radiantlamp heating, infra-red heating, kinetic energy transfer by energeticparticle bombardment, e.g., electron-beam heating, etc. The localheating is performed by selectively applying a suitable source 4intensity for a duration sufficient to achieve a desired temperaturewithin a desired depth below upper surface 2U of a patterned pluralityof local areas of the amorphous, paramagnetic or anti-paramagnetic layer2. Pattern definition can be accomplished by various techniques,including, inter alia, scanning of focussed photon irradiation orenergetic particle beams over the surface of the amorphous layer orpassage through an apertured mask overlying the surface of the amorphouslayer, the mask including a pattern of openings corresponding to thedesired pattern of magnetic particles or grains 3 to be formed in theamorphous layer. In addition to the above-described technique whereinlocalized heating by photon irradiation is accomplished by means ofimage projection, other photon irradiation techniques may be employed tosimilar effect, including, for example, interference lithography,contact lithography, and spot scanning. Similarly, energetic particlebombardment can be accomplished by means of, for example, scanning andmask imaging techniques.

According to the invention, complete crystallization of the selectivelyphoton irradiated or energetic particle bombarded areas is not requiredin order to form functional ferromagnetic particles or grains 3. As aconsequence, it is not necessary that the selective, locally photonirradiated or energetic particle bombarded areas reach temperatures ashigh as the melting point of the amorphous material during irradiationor bombardment, and local heating to temperatures below the meltingpoint can, depending upon the particular material of the amorphouslayer, result in formation of ferromagnetic particles or grains 3capable of recording and reading-out data/information stored therein.Given the disclosure and objectives of the present invention,determination of suitable photon irradiation or energetic particlebombardment conditions can be readily determined and selected by one ofordinary skill in the art for use with a particular amorphous,paramagnetic or anti-paramagnetic material. For example, lasers suitablefor use as a photon irradiation source with metallic glass materialsaccording to the present invention can have wavelengths ranging from thedeep ultra-violet (“DUV”) to the ultra-violet (“UV”) to the visible andeven infra-red (“IR”) regions of the electromagnetic spectrum, with theshorter wavelength DUV-UV regions being preferable from the point ofview of higher pattern resolution. The lasers may also be pulsed, withpulse durations ranging from below about one nanosecond (<10⁻⁹ sec.), toabout one microsecond (10⁻⁶ sec.), typically about 3-50 nanoseconds.

EXAMPLE

From about 5 to about 15 μm thick layers 2 of amorphous, paramagneticNi—P were deposited on Al-based disk substrates 1 by conventionalplating or vacuum deposition techniques (e.g., electroless plating,electroplating, sputtering) and given a smooth (i.e., Ra<5 Å) uppersurface 2U by conventional polishing techniques, to accommodate a lowflying height slider (i.e., <1 μinch). Pulsed laser DUV to UV photonirradiation sources 4 (pulse width 3-50 nanoseconds) were utilized forfocussing and projecting a 2-dimensional image in the form of acheckerboard pattern with a 1 μm×2 μm unit cell size onto the uppersurface 2U of the amorphous Ni—P layer 2. FIGS. 3(A) and 3(B) aredrawings respectively of Atomic Force Microscopy (AFM) and MagneticForce Microscopy (MFM) images obtained when the laser output power andduration were selected to provide the pattern of locally heated areaswith a temperature close to the crystallization phase transitiontemperature of amorphous Ni—P, i.e., about 300-350° C. FIGS. 4(A) and4(B) are analogous to FIGS. 3(A) and 3(B), but illustrate the case wherethe laser output power was reduced such that the maximum temperature ofthe locally heated areas achieved during laser irradiation was below themelting point of amorphous Ni—P in the former i.e., at the higher laseroutput power, both the AFM and MFM images clearly show a checkerboardpattern of ferromagnetic particles or grains corresponding to the laserirradiation pattern, whereas, in the later instance, i.e., with reducedlaser output power, the checkerboard pattern indicating formation offerromagnetic particles or grains is clearly visible only in the MFMimage. A grater volume change of the irradiated areas due tocrystallization into ferromagnetic Ni particles or graims was observedwhen the higher rather than the lower laser power output was utilized,and crystallization at the higher laser output power occurred to a depthof about 50 Å below upper surface 2U of layer 2.

Thus, it is evident that the inventive methodology, which is largelybased upon conventional magnetic media manufacturing technology, can beeffectively utilized for facilitating rapid, convenient, andtechnologically simplified fabrication of patterned magnetic media atproduct throughput rates consistent with the requirements of low costautomated magnetic media manufacture. Moreover, while the Exampleillustrates an embodiment wherein a checkerboard type two-dimensionalpattern is formed, the invention is not limited to formation of anyparticular geometric pattern or arrangement of magnetic particles, andthe formation of patterns of other shapes, designs, or arrangements iswithin the ambit of the present invention.

In the previous description, numerous specific details are set forth,such as specific materials, structures, processes, etc., in order toprovide a better understanding of the present invention. However, thepresent invention can be practiced without resorting to the detailsspecifically set forth. In other instances, well-known processingtechniques have not been described in detail in order not tounnecessarily obscure the present invention.

Only the preferred embodiments of the present invention and but a fewexamples of its versatility are shown and described in the presentdisclosure. It is to be understood that the present invention is capableof use in various other combinations and environments and is susceptibleof changes and/or modifications within the scope of the inventiveconcepts as expressed herein.

What is claimed is:
 1. A method of manufacturing a high areal storagedensity, patterned magnetic data/information recording, storage andretrieval medium, which method comprises the sequential steps of: (a)providing a non-magnetic substrate having a surface for layer formationthereon; (b) forming a layer of an amorphous, paramagnetic oranti-paramagnetic material on said substrate surface, said layer ofamorphous, paramagnetic or anti-paramagnetic material comprising atleast one component which is ferromagnetic when in at least partiallycrystallized form; and (c) at least partially crystallizing said atleast one component of said layer of amorphous, paramagnetic oranti-paramagnetic material at selected locations thereof to thereby forma pattern of at least partially crystallized, ferromagnetic particles orgrains of said at least one component of said layer, said ferromagneticparticles or grains being spaced apart and surrounded by a matrix ofsaid amorphous, paramagnetic or anti-paramagnetic material.
 2. Themethod according to claim 1, wherein: step (b) comprises forming as saidamorphous, paramagnetic or anti-paramagnetic layer a metal glass layerincluding at least one metal element which is ferromagnetic when in atleast partially crystallized form.
 3. The method according to claim 2,wherein: step (b) comprises forming a metal glass layer comprising atleast one metal element selected from the group consisting of iron (Fe),nickel (Ni), cobalt (Co) as said amorphous, paramagnetic oranti-paramagnetic layer.
 4. The method according to claim 1, wherein:step (c) comprises at least partially crystallizing said at least onecomponent of said amorphous, paramagnetic or anti-paramagnetic layer byincreasing the temperature of said layer at said selected locations. 5.The method according to claim 4, wherein: step (c) comprises increasingthe temperature of said layer at said selected locations up to at leasta phase transition temperature of said at least one component.
 6. Themethod according to claim 5, wherein: step (c) comprises increasing thetemperature of said layer at said selected locations up to the meltingpoint of said at least one component thereof.
 7. The method according toclaim 4, wherein: step (c) comprises increasing the temperature of saidlayer at said selected locations by irradiation with photons orenergetic particles.
 8. The method according to claim 7, wherein: step(c) comprises photon irradiation utilizing a focussed laser or afocussed, high-intensity lamp as a source of photons.
 9. The methodaccording to claim 7, wherein: step (c) comprises utilizing an electronbeam as a source of energetic particles.
 10. The method according toclaim 7, wherein: step (c) comprises scanning said photons or saidenergetic particles across the surface of said layer to impingethereupon at said selected locations, or irradiating said photons orenergetic particles through an aperture-patterned mask having aplurality of openings extending therethrough with predetermineddimensions corresponding to a preselected size of said at leastpartially crystallized, ferromagnetic particles or grains.
 11. Themethod according to claim 7, wherein: step (c) comprises forming atwo-dimensional pattern.
 12. The method according to claim 11, wherein:step (c) comprises forming a checkerboard pattern.
 13. The methodaccording to claim 1, wherein; step (a) comprises providing anon-magnetic, disk-shaped substrate comprising a material selected fromthe group consisting of: metals, metal alloys, aluminum (Al), Al-basedalloys, ceramics, glasses, polymers, and composites thereof; step (b)comprises forming a layer of amorphous nickel-phosphorus (Ni—P) as saidamorphous, paramagnetic or anti-paramagnetic material; and step (c)comprises increasing the temperature of said amorphous Ni—P layer atsaid selected locations to up to about 350° C. for an intervalsufficient to form and at least partially crystallize ferromagnetic Niparticles or grains thereat.